Internal-combustion engine



NOV. 2 1926;

1,605,286 c3. E. RucKsTELL INTERNAL COMBUSTION ENGINE Filed Jan. 18, 1922 A 7' TOP/Vf Y Patented Nov. 2, 1926.

UNITED ,srarss Parent vorlicr.

instaat GLOVEB. EDWIN RUCKSTELL, F BERKELEY, CALFORNI-A.

INTEnNAL-coMBusTron Enc-inn.

Application filed January 18, 1922. Serial No. 530,039.i

efficiency. The aim of all designers of high` speed engines is for a high volumetric efliciency, and one way of accomplishing this is to ram an excess charge into the combustion chamber. gines obtain this rammed charge by arranging the firing order of the cylinders so ias to benefit tothe greatest extent by the vvelocity or rate ofiiow vofthe gases `in the manifold. (For instance, ina four-cylinder engine using a single intake manifold and having a firing order. of .one-three-four-two, it will be seen that at the time No, l opens to receive'a charge the gases in the manifold are moving` at high velocity iii thefdirection of Nodion` account ofhaving just heen` acted upon by cylinder No. 2,' and, similarly, when cylinder No. 4takesin a charge, gases are flowing in. its direction by reason of the preceding induction stroke of cylinder No. 3. `ln racing car engines the rate of flow of these gases through the manifold is -in excess of 250 feet per second, and,

since the mixture of fuel and `air possesses weight, it follows that considerable inertia or head will be present when the gases reach the ends of the manifold adjacent cylinders Nos. l and 4.

l@ The effect of this will be to ram an excess charge into these end cylinders. However, this plan fails to take into account the loss of compression pressure occurring in cylinders Nos. 2 `and 3 which results from the @i duty imposed upon these cylinders of overcoming the inertia and reversing the direction of flow of these rapidly moving gases in the manifold. Thus, when cylinder No. 3 starts its induction stroke, cylinder No. l

-10 has just finished and the gases are then piled up in the opposite end of the manifold.

Similarly, when No. 2 starts its induction stroke No. 4 has just closed and the gases are piled up in the other end of the manifold. As already stated, these gases possess inertia and that inertia must not only be 'about hy these cylinders.

a partially closed throttle.

Designers of racing carenovercomel by cylinders Nos. 2.and 3, but, in addition, a complete reversal in the direc.- tion of fiow of the gases mustV be brought The effect thus produced upon cylinders Nos. 2 and 3 ,is analogous to that of a. cylinder 'running on mum efficiency, out of the engine the compression pressures in all the cylinders Ashould be approximately equal.Y "The present invention contemplatesthe equalizing of these pressures in all cylinders without losing the eiilect of the rammed charges.

One method of accomplishing this is set To get the maxiforth in the following description and illustrated in the accompanyingdrawing,1in which- Fig. l shows a diagram of af conventional j type of four-cylinder engine andmanifold connections therefor.V Y e Fig. 2 shows a diagram illustrating in vertical crosssection an arrangement of cyll inders suitable for accomplishing the ,object of this invention. A i

Fig. 3 shows amodiiied form of the invention using two caibureters'for a four-cylinder engine.

Referring tothe arrangement shown in Fig. l, the cylinders of a conventional type of engine are designated in successive order by the numerals 1', .2,L 3 and `4and an vintake manifold isshown at l0. Assuming the iiriiig orders of these cylinders vto be 1 3 4 2, it will he seen that after cylinder No. l has taken in its charge the gasesv are piled up in the neighborhood of its in: take at one end of the manifold. Cylinder No. 3 following with its suction stroke must overcome the inertia of these gases and reverse the direction of their flow.` Keeping in mind the fact that the engine is operating at high speed and that the gases possess an appreciable weight, it will be seen that cylinder No. 3 will receive a rareiied charge. The period of induction in a high speed engine is very small, and, in the space of time allotted, the inertia of these gases cannot be overcome. Cylinder No. 4, however, being adjacent cylinder No. 3 will open at a time to receive the benefit of the velocity and direction of flow of the gases initiated by cylinder No. 3, and the result will be a piling up of the gases at the intake of cylinder No. 4, thereby producing a rammed charge in the last-named cylinder. Cylinder No. 2 now opens to a condition where theV Aso gases in the manifold are piled up in the opposite end and it therefore is handicapped to the same extent as cylinder No. 3. The movement of gases initiated by cylinder No. 2 will, however, benefit cylinder No. l. rIhe same alternating high anl low charges occur' in any other usual firing order, such as l--Q-/l-S, in Which case cylinders Nos. 2 and 3 will receive rammed charges and the cylinders Nos. l and 4 reduced charges.

Thus, it can be seen that if the compression space in all cylinders be equal, the compression ratio and the mean effective pressure of those cylinders receiving reduced charges Will be comparatively low, Whereas the compression ratio and the mean effective pressure of those cylinders receiving rammed charges Will be much higher. It is Well known that the mean effective pressure throughout the piston strokeV and the eiliciency of the power charge are dependent upon the compression ratio.

These unequal compression pressures mean that tivo cylinders are giving maximum eiiiciency and the other two are not. To overcomethis I reduce the clearance volume of those cylinders receiving reduced charges to an extent sufficient to raise their compression pressures to the equal of the other cylinders. This may be accomplished, as shown in Fig. 2, by employing pistons 11 of one length in cylinders firing alternately and pistons l2 of a different length in cylinders firing intermediately, thus giving; less clearance volume in the cylinders which, on account of their position and firing order, do not receive rammed charges.

Other Ways of accomplishing this result will readily suggest themselves to those skilled in the art. For instance, a reduction in the compression space in the cylinders receiving reduced charges can be brought about by forminga smaller core in the heads of those cylinders or by giving the pistons therein a longer stroke than the pistons of the remaining cylinders.

In Fig. 3 each pair of cylinders has its own carbureter. An intake manifold 13 is used for cylinders l and 2 and a separate manifold 14- for the cylinders 3 and il. In this form, and assuming a firing' order of l--3-l-Q, it will be seen that No. l Will open for induction immediately followingl the suction stroke of No. 2. The flow of gas thus started from the carbureter by No. 2 Will ram cylinder No. l. Likewise cylinder No. L Will be charged by the gases started by No. 3. However, cylinder No. 2 will open for intake so long after the suction stroke of No. l that the gases in the manifold will not be in motion, and, therefore, part of the effect of the suction stroke in No. 2 will be lost in startinga the `gases in motion through the manifold. The same is true of cylinder No. 3.

I-Iaving thus described my invention, what I claim and desire to secure by Letters Pat ent is:

A. high speed engine of the four-stroke cycle type including multiple cylinders and a single intake manifold for adjacent cylinders, the cylinders Which have to overcome the inertia of the flow of gases in the manifold by reason of their position and firing order having less vclearance volume, and those which, on account of their position and ring order, are assisted by the inertia of the gases in the manifold created by the induction strokes of the other cylinders having greater clearance volume.

GLOVER EDVIN RUCKSTELL. 

